Neurobites – Meningoencephalocele (brain in nose)

Every week, the BVNS neurologists, residents and interns convene to discuss a human or veterinary neurology/neurosurgery article.

NeuroBites is a digestible synopsis written by Dr. Bush of the article covered in journal club.

Welcome to NeuroBites.


Lazzerini K, et al. Clinical Features, Imaging Characteristics, and Long-term Outcome of Dogs with Cranial Meningocele or Meningoencephalocele. J Vet Intern Med 2017;31:505–512 DOI: 10.1111/jvim.14638

Click HERE for the full article..

What is the scientific term for having your brain in your nose?
A meningoencephalocele that crosses the ethmoid or frontal bone into the nasal cavity is when you have brain in your nose.

What is the scientific term for having a pocket of CSF wrapped in meninges outside of your skull?
This is called a meningocele.

Is this condition common and how would we recognize it in dogs?
No, it is not common. In today’s journal club, Dr. Trub presented a case series of 22 dogs that were collected 10 years ago from 6 specialty clinics. Common signs were:

Seizure (mostly generalized) – 77%

Abnormal behavior – 31% included aggressiveness, compulsive behavior, hyperactivity, yelping, star gazing or fly catching

Having some of your brain in your nose can also cause no clinical signs.

What kind of dogs get this problem?
Mostly young dogs (average was 6.5 months) but could be as old as 8 years of age – no particular breed seems at risk but there were 2 border collies. Typically this is a congenital problem but it can also be seen with trauma.

Want to hear about 2 funny words?
Cranioschisis – sounds to me like this is when you have to poop so bad you have a headache but real meaning is more simple – it is an opening in the cranium that should not be there.

Rhinorrhea – sounds to me that this is a STD in the rhinoceros however it means the flow of CSF out the nose – presumably from a tear in the meninges from head trauma.

Is it bad to have brain in your nose?
Well it ain’t good and in human medicine is considered a surgical condition in an effort to control refractory seizure. In dogs, it depends on how much brain you have in your nose – mild cases live a long time, moderate cases have about a 50% survival and succumb to euthanasia for perceived poor prognosis or refractory seizure, and severe cases have only a 20% survival.

How does today’s article change things?
It might make us a little more inclined to perform the key diagnostic test (MRI) in younger dogs even when they have a normal exam (25% of cases had no hints in neurological exam that they had brain in their nose). In specific I am thinking about the 2 border collies in this study and all the cases of young dog seizure in border collies that I have assumed were genetic and not structural.

Lastly, if I have a case and it is not responding to medication then maybe I would consider surgery. There is a case report of surgery curing refractory seizure in a case of an intranasal meningoencephalocele.

Want to see a picture… the red arrow shows the part in the nasal sinus

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